The sprinklers in these systems are attached to pipes containing pressurized water at all times. Individual sprinklers in the vicinity of a fire are set off by heat, allowing water to flow through them immediately. Wet-pipe systems are used wherever temperatures are high enough to prevent freezing. When water freezes it expands. Burst pipes may render a system inoperable and can cause significant water damage.Sometimes, an anti-freeze solution is added to certain sections in a wet-pipe system to prevent freezing.